The e-commerce giant announced Tuesday that it is partnering up with Warren Buffett's investment firm Berkshire Hathaway and US bank JPMorgan Chase to lower healthcare costs for US employees at these companies, Reuters reported.

The announcement sent ripples through the healthcare market; the share price at US pharmacies CVS and Walgreens dropped between 4.5% to 6% in premarket trading and UnitedHealth insurance company dropped 6.2%, Reuters reported.

Amazon is known for its aggressive growth and when it thrives, other companies suffer.

Electronics companies

While Best Buy has been under siege by Amazon for years, the electronics retailer long had one advantage — the Geek Squad of employees ready to help customers with technical difficulties.

However, Recode reported in July that Amazon was rolling out a Geek Squad of its own, in the form of "army of in-house gadget experts to offer free Alexa consultations as well as product installations for a fee."

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Consumer staples

The future of batteries may be online — and that's bad news for companies like Energizer.

While online sales of batteries only make up roughly 5% of total battery sales today, UBS said in a note last year that it expects that figure to rise to 17% by 2025. With Amazon making up roughly 90% of online battery sales and its own private label battery brand, it could create some major complications for Energizer.

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Department stores

Drew Angerer/ Getty

Macy's and other department stores, such as JCPenney, are facing off against Amazon — and coming up short.

"Internet retailers (led by Amazon) have added $27.8 billion to their apparel revenue since 2005, while dept stores have lost $29.6 billion," Morgan Stanley analysts wrote in a 2016 note. "This share loss appears at risk of accelerating given 1) Amazon's bigger push into fashion, and 2) consumer willingness/acceptance to shop fashion through Amazon."

Launching the Prime Wardrobe service in June was "another nail into the department store coffin," Wells Fargo analyst Ike Boruchow wrote in a note to clients.

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High-end department stores

"Amazon knows more about the consumer than they do," CNBC's Jim Cramer wrote after Nordstrom reported another disappointing quarter in May. "They — the best out there — are still doing guesswork, with one brick-and-mortar hand tied behind their backs."

And in October, Scott Galloway, a professor of marketing at NYU Stern School of Business who correctly predicted the company would buy Whole Foods, said Amazon may buy Nordstrom next.

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Food delivery businesses

In September, Amazon partnered with Olo, an online ordering company, to help it ramp up its food delivery service and take on GrubHub, the parent company of Seamless.

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Book stores

Mike Segar/Reuters

The Barnes & Noble versus Amazon battle has been going on for years. However, the discrepancy between the two has been especially grim recently.

Barnes & Noble reported in January that sales dropped 6.4% during the holiday season. E-commerce sales also suffered during the critical period, dropping 4.5%.

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Grocery stores

FILE PHOTO: A customer pushes a shopping cart at a Walmart store in Chicago
Thomson Reuters

Amazon bought Whole Foods in August 2017, which dealt a massive blow to US grocery stores as it forced its way into the brick and mortar market and threatened to drive prices down.

The retailer is already the largest seller of groceries online. It estimated to have 18% of the US online grocery market, which is double the second place share held by Walmart.

By having access to brick and mortar locations, the company is able to expand its reach across the US and use these stores as distribution centers for online orders.

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Healthcare companies

Thompson Reuters

Amazon's latest venture with Buffett's Berkshire Hathaway and JPMorgan Chase & Co threatens to have a big impact on the US healthcare market.

The three companies are looking at ways to offer more affordable healthcare for employees and their families using technology solutions, Reuters reported.

"The ballooning costs of healthcare act as a hungry tapeworm on the American economy," Berkshire Hathaway Chairman and CEO, Warren Buffett said. "Our group does not come to this problem with answers. But we also do not accept it as inevitable," Reuters reported.